H89 as serial terminal

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sat Mar 29 16:36:00 2003

> > > lets you choose, all of my '89's are down right now. :-/
> >
> > What's wrong with them? These machines are not exactly complicated or
> > hard to fix (at least not compared with some machines I've worked on).
> >
> > -tony
> >
>
> Tony,
>
> One, new to me, is popping caps and just needs a little TLC, I think; I

If you're lucky that will just be old capacitors that have decided to
fail. If you're unlucky, it'll be a PSU problem (bad ground on one of the
3 terminal regulators?) that means that one of the supply lines is way
overvoltage. Which will then kill the capacitors _and chips_.

[...]

> for all of these machines plus some). You're correct, they're not hard to
> work on; having little time and fat fingers not well-suited to tight spaces
> have been my biggest barriers. I've got another project going right now,

The rule I discovered when working on my Z90 was 'Think what order the
various bits were made/installed, and take the latest ones out first'. In
other words, take ou the disk drive, then the expansion PCBs, then the
CPU board, and finally the terminal logic board (OK, and then the monitor
parts if you have to).

-tony
Received on Sat Mar 29 2003 - 16:36:00 GMT